Crystal structure of catena-bis(μ-dicyanamido)-bis[2-(4-pyridyl)- 4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide-κN)zinc(II) — 2-(4-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (1:2), Zn(C12H16N3O2)2(C2N3)2 · 2C52H64N18O8

Abstract

C 52 H 64 N 18 O 8 Zn, monoclinic, P2 1 /n (no. 14), a =17.825(2) Å, b =7.3268(7) Å, c =21.182(2) Å, b =92.902(1)°, V =2762.8 Å 3 , Z =2,R gt (F) =0.037, wR ref (F 2 ) =0.093, T =294 K. Source of materialThenitronylnitroxide radical 2-(4-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (NITpPy)w as prepared according to [1].The Zn(NITpPy) 2 (N(CN) 2 ) 2 ) × 2NITpPy was synthesized by adding Na[N(CN) 2 ](0.045 g, 0.5 mmol) to 20 mL of an ethanol solution containing Zn(OAc) 2 × 6H 2 O(0.0112 g, 0.5m mol) and NITpPy (0.248 g, 1mmol). The mixture was stirred for 5hat room temperature and then filtered off. Thed ark filtrate was allowedtostand at room temperature. Darkcrystals suitable for X-ray analysis were obtained after three weeks. Elemental analysis-found:C,55.10 %; H, 5.72 %; N, 22.32 %; calculated for C 52 H 64 N 18 O 8 Zn: C, 55.04 %; H, 5.69 %; N, 22.22 %. IR data areavailable in the CIF file. DiscussionAlarge number of multidimensional complexes linked by means of different bridging ligand systemssuch as azido, 4,4'-bipyridine andoxalate have markedly increased in the past fewyears [2,3]. It has also been documented that dicyanamide can be regarded as an idealligandtoconstructpolymers, due to the rich structural and topological features along with the magnetic properties related to this ligand. On the other hand, the nitronylnitroxide radicals acting as useful paramagnetic building blocks have been extensively used to assemble molecular magnetic materials [4][5][6][7]. Taking advantage of theabilitiesofbothnitroxide radicals andthe above mentioned kind of anions to coordinate transition metals, we are dealing with the use of the dicyanamide anions as bridging ligands. In the title crystal structure, the anion [N(CN) 2 ]-acts as end-toend bridging ligand giving rise to achain structure. The Zn atom is bonded to two apical NITpPy units and four equatorial N(CN) 2 units which bridge adjacent metal sites. The distorted octahedral metal site is located on an inversion center, therefore, both radicals anddicyanamide anions areintrans positions. The crystal structure consists of infinite chains of Zn(NITpPy